"He's the same guy that I think he was four years ago," the U.S. attorney general told ABC's Pierre Thomas in a wide-ranging, exclusive interview on Wednesday. Thomas asked Holder about the weight of dealing with national-security and other issues, and how being in office has changed the two men.

"He's a serious person, he takes these matters extremely seriously," Holder said. "He's a good leader in that way-he motivates us. I think he understands how this wears, has the potential to wear people down. he's always exhorting us to keep at it the best way that we can but always telling us to try to find ways in which we do get away."

Obama, Holder says, is the one member of his team who never gets a break.

"I worry about him sometimes, you know, because he's the one guy who can't get away," Holder said.

The attorney general also said his relationship with the president has grown distant over the last few years, as his work requires independence from the White House.

As the government's top prosecutor, Holder is expected to maintain some distance from the president and his aides to avoid the appearance of politics affecting the Justice Department's legal decisions.

ABC's Pierre Thomas asked Holder if the president is his friend, his colleague, or his boss.

"He's all of those things," Holder said. "Our relationship has changed since I've been attorney general-there has been a distancing because as attorney general, I have to be independent. I look forward to the days when we can just be Eric and Barack again and hang out."

Working in the administration has weighed on Holder, the attorney general told ABC News, while declining to predict when he'll leave it-even as fellow Cabinet members have departed after the end of Obama's first term.

Since he began his current job, Holder has received daily briefings on national security threats and has kept tabs on emerging terrorist plots, among other presumably high-stress responsibilities.